JP2017110259A - Combustion state measuring method, and combustion state measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion state measuring method and a combustion state measuring system capable of confirming a combustion state in a tuyere in fine coal combustion.SOLUTION: A combustion state measuring method includes: installing a combustion state measuring apparatus 4 in a position of a distance L(0 mm<L<D) from the tip of a lance 3, between a distance D of 0-500 mm from the tip of the lance 3 to the tip of a tuyere 1; and continuously measuring a fine coal combustion state in the tuyere with the combustion state measuring apparatus. A combustion state measuring system includes: a tuyere installed in the wall surface of a blast furnace; a blow pipe mounted on the tuyere; a lance mounted on the wall surface of the blow pipe; and a combustion state measuring apparatus between the tip of the lance and the tip of the tuyere, mounted on the wall surface of the tuyere or the blow pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a combustion state measuring method for measuring a combustion state of a solid fuel such as pulverized coal or an easily combustible gas such as LNG (Liquefied Natural Gas) at a blast furnace tuyere.

In recent years, global warming due to an increase in carbon dioxide emission has become a problem, and the suppression of exhausted CO ₂ is an important issue even in the steel industry. As a result, in recent blast furnace operations, the ratio of low reducing agent ratio (low RAR: Abbreviation for Reduction Agent Ratio, the total amount of reducing material blown from the tuyere and coke charged from the top of the furnace per 1 ton of pig iron production. ) Operation is strongly promoted. Blast furnaces mainly use coke and pulverized coal blown from the tuyere as a reducing material. In order to achieve a low reducing material ratio, and in turn, to suppress carbon dioxide emission, coke is used as waste plastic, LNG, heavy oil and other hydrogen. A method of replacing with a reducing material having a high content is effective.

  In Patent Document 1 below, humans have conventionally observed the brightness of the tuyere directly to determine the furnace condition of the blast furnace, but in order to determine more accurately, an apparatus for observing the raceway is installed at the rear end of the blow pipe. It is stated that it is installed and observed. It is possible to observe the coke and molten slag in the furnace and the combustion status of pulverized coal from the optical information generated on the raceway by the device.

  Further, in Patent Document 2 below, as in Patent Document 1, it is described that a device for observing the raceway is installed at the rear end of the blow pipe and the tuyere situation is observed. From the occurrence of the pulverized coal expansion phenomenon in which the image of unburned pulverized coal from the lance rapidly expands in the photographed image of the tuyere, information is obtained that the shape of the raceway has changed from the normal state.

  Further, Patent Document 3 below attempts to stabilize blast furnace operation by installing a sonde at the blast furnace tuyere and detecting and spectroscopically measuring light in the flame of pulverized coal to maintain proper combustion.

JP-A-2-182817 JP 2013-185234 A Japanese Patent Laid-Open No. 10-30105

  In Patent Document 1, a device for measuring the raceway portion of the blast furnace is installed in the observation window at the rear end of the blow pipe, and the combustion state of pulverized coal is observed from optical information generated in the raceway portion. Detailed information such as where pulverized coal combustion starts from the lance is not known, and it is impossible to feed back the information to the blast furnace operation in real time because it is necessary to analyze the recorded image separately.

  Moreover, in the said patent document 2, although the apparatus which measures a raceway part is installed in the observation window of the rear end of a blow pipe, the situation of a raceway is judged from the measurement result of pulverized coal expansion, It is not an apparatus and a form for judging the quality of combustibility.

  Further, in Patent Document 3, a sonde is installed at the blast furnace tuyere, and the light in the combustion flame by the pulverized coal is detected by the sonde, and the combustibility of the pulverized coal is controlled by spectroscopic measurement. Since it is a measurement related to the tuyere cross section, information on the combustion state at a distance from the tip of the lance cannot be obtained. In addition, since there is no description regarding the installation position of the sonde, there is a possibility that light emission due to pulverized coal combustion or light emission due to coke combustion cannot be determined depending on the position. Therefore, it may be difficult to evaluate the flammability of pulverized coal.

  The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide a combustion state measuring method that enables confirmation of the combustion state at the tuyere during pulverized coal combustion. is there.

  That is, according to the present invention, when the distance D from the tip of the lance to the tip of the tuyere is between 0 and 500 mm, the combustion condition measuring device is installed at a position of a distance L (0 mm <L <D) from the tip of the lance. It is a combustion state measuring method characterized by continuously measuring the pulverized coal combustion state at the tuyere with a measuring device.

In the combustion state measuring method according to the present invention,
(1) The combustion state measuring device is a pressure gauge, and the pulverized coal combustion state is a pressure measured using a pressure gauge,
(2) The combustion state measuring device is a temperature measuring device, and the pulverized coal combustion state is a temperature measured using a temperature measuring device,
(3) The temperature measuring device is a two-color thermometer that measures particle surface temperature from luminance or a thermocouple that measures flame temperature,
(4) The combustion state measuring device is an area ratio distribution measuring device, and the pulverized coal combustion state is an area ratio of pulverized coal measured using an area ratio distribution measuring device,
(5) The combustion state measuring device is an image analysis device, and the pulverized coal combustion state is a flame part area of pulverized coal measured using an image analysis device,
However, it can be considered as a more preferable solution.

  According to the present invention, when the distance D from the tip of the lance to the tip of the tuyere is between 0 and 500 mm, the combustion state measuring device is installed at the position of the distance L (0 mm <L <D) from the tip of the lance. By continuously measuring the pulverized coal combustion state in the tuyere with the measuring device, it is possible to confirm the combustion state in the tuyere during pulverized coal combustion.

It is a figure for demonstrating an example of the system which implements the combustion condition measuring method of this invention. (A), (b) is a graph which shows an example of the measurement result using a pressure measuring device as a combustion condition measuring device, respectively. (A), (b) is a graph which shows the other example of the measurement result using a pressure measuring device as a combustion condition measuring device, respectively. (A), (b) is a graph which shows the further another example of the measurement result using a pressure measuring device as a combustion condition measuring device, respectively. (A), (b) is a graph which shows an example of the measurement result using the temperature measuring apparatus which consists of a two-color thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the other example of the measurement result using the temperature measuring apparatus which consists of a two-color thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the further another example of the measurement result using the temperature measuring apparatus which consists of a 2 color thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows an example of the measurement result using the temperature measuring apparatus which consists of a thermocouple thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the other example of the measurement result using the temperature measuring apparatus which consists of a thermocouple thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the further another example of the measurement result using the temperature measuring apparatus which consists of a thermocouple thermometer as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows an example of the measurement result using an area ratio measuring device as a combustion condition measuring device, respectively. (A), (b) is a graph which shows the other example of the measurement result using an area ratio measuring apparatus as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the further another example of the measurement result using an area ratio measuring apparatus as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows an example of the measurement result using an image analyzer as a combustion condition measuring device, respectively. (A), (b) is a graph which shows the other example of the measurement result which used the image-analysis apparatus as a combustion condition measuring apparatus, respectively. (A), (b) is a graph which shows the further another example of the measurement result which used the image-analysis apparatus as a combustion condition measuring apparatus, respectively.

  FIG. 1 is a diagram for explaining an example of a system that implements the combustion state measuring method of the present invention. In FIG. 1, 1 is a tuyere installed on the wall of a blast furnace (not shown), 2 is a blow pipe attached to the tuyere 1, 3 is a lance attached to the blow pipe 2, and 4 is installed at a predetermined position of the lance 3. This is a combustion state measuring device. D (mm) is the distance from the tip of the lance 3 to the tip of the tuyere 1, and L (mm) is the distance from the tip of the lance 3 to the combustion state measuring device 4.

  The combustion state measuring method of the present invention is characterized in that the combustion state measuring device 4 is installed in the tuyere 1 in a system in which the distance D (mm) from the tip of the lance 3 to the tip of the tuyere 1 is set to 0 to 500 mm. In this case, the combustion state measuring device 4 is installed at a distance L (0 mm <L <D) from the tip of the lance 3, and the combustion state measuring device 4 continuously measures the pulverized coal combustion state in the tuyere 1.

  Here, the reason why the distance D (mm) from the tip of the lance 3 to the tip of the tuyere 1 is set to 0 to 500 mm is as follows. That is, if the distance D is less than 0 mm, the pulverized coal is not blown from the lance, so that it is impossible to measure the combustion state of the pulverized coal. On the other hand, if the distance D exceeds 500 mm, the correlation between the measured combustion state of the pulverized coal and the combustion condition is not possible. Therefore, 500 mm was set as the upper limit.

  As the combustion state measuring device 4 used in the combustion state measuring method of the present invention, for example, various devices that measure various physical phenomena occurring in a blast furnace can be used. Among them, a pressure measuring device and a temperature measuring device can be used. It is preferable to use an area ratio distribution measuring device and an image analyzing device. Hereinafter, embodiments in the case where a pressure measuring device, a temperature measuring device, an area ratio distribution measuring device, and an image analyzing device are used as the combustion state measuring device 4 will be described in order.

Example 1: Example of pressure measurement A tuyere 1 equipped with a pressure measuring device as a combustion state measuring device 4 was installed in a blast furnace, and continuous pressure measurement at the tuyere 1 was performed. Specifically, in order to confirm the combustion status of pulverized coal at the tuyere, in a blast furnace with an inner volume of 5000 m ³ and 38 tuyere, a pressure measuring device 4 is installed in one tuyere as shown in FIG. It installed in the position of L = 150mm (D = 500mm and all are in a tuyere). As measurement conditions, pulverized coal was blown from the lance at a hot metal production amount of 11500 t / day and a pulverized coal ratio of 150 kg / t-hot metal. Further, air having a blowing temperature of 1200 ° C., a flow rate of 7000 Nm ³ / min, and an oxygen concentration of 27% was blown from the blow pipe 2. The pressure was measured continuously for 1 day. A commercially available pressure gauge was used as the pressure measuring device 4.

  The measurement results are shown in FIG. In the example shown in FIG. 2, FIG. 2A is a graph showing the relationship between pressure and time at L = 50 mm, and FIG. 2B is a graph showing the relationship between pressure and time at L = 150 mm. It is. From the results shown in FIG. 2, it can be confirmed that the pressure at the tuyere during pulverized coal combustion can be continuously measured in a state where the variation of the pressure with respect to time is small.

Also, the oxygen concentration during blowing is 21% or 23 under conditions of 11500 t / day hot metal production, 150 kg / t-pulverized coal ratio, blowing air temperature 1200 ° C. and blowing air flow rate 7000 Nm ³ / min. %, The pressure at the tuyere when operated for 1 day each was measured at a position of L = 50 mm and 150 mm. The results are shown in FIG. 3 and FIG. In the example shown in FIG. 3, FIG. 3 (a) is a graph showing the relationship between pressure and time at L = 50 mm and an oxygen concentration of 21%, and FIG. 3 (b) is a graph showing L = 150 mm and an oxygen concentration of 21%. It is a graph which shows the relationship between the pressure of this and time. In the example shown in FIG. 4, FIG. 4 (a) is a graph showing the relationship between pressure and time at L = 50 mm and an oxygen concentration of 23%, and FIG. 4 (b) is a graph showing L = 150 mm and an oxygen concentration of 23%. It is a graph which shows the relationship between the pressure of this and time. From the results of FIG. 3 and FIG. 4, the pressure at the tuyere is the average when the operation is performed with the oxygen concentration shown in FIG. 3 being 21%, compared with the case where the operation is performed with the oxygen concentration shown in FIG. It turned out to be low. This is thought to be because the pressure at the tuyere decreased because the combustion temperature decreased and the amount of reducing gas generated by the combustion of pulverized coal decreased when the combustibility of pulverized coal decreased.

  Next, the average coke ratio for one day is recorded in two operations: when maintaining the flammability of pulverized coal by measuring pressure at the tuyere and when operating without performing pressure measurement at the tuyere. Thus, the effect of pressure measurement at the tuyere was confirmed.

The operating conditions are 11500 t / day hot metal production, 150 kg / t-hot metal pulverized coal ratio, flow rate 7000 Nm ³ / min is constant, and any one of air temperature, oxygen concentration during air blowing, and pulverized coal volatiles is changed Then, the pressure at the position of L = 50 mm in the tuyere was measured. Under each condition, the weight ratio of -74 μm pulverized coal was adjusted so that the pressure at the tuyere was as constant as possible. The results are shown in Table 1 below. In Table 1, test conditions levels 4, 6, and 8 are examples in which operation is performed to maintain flammability of pulverized coal by pressure measurement at the tuyere, and test conditions levels 1, 3, 5, and 7 are It is an example at the time of operating, without implementing the pressure measurement in a mouth. In Level 2, only the average pressure was measured under the same conditions as Level 1, and no pressure adjustment was performed.

  From the results of level 2 and level 4, it was confirmed that the pressure at the tuyere increased from 360 kPa to 370 kPa by increasing the blowing temperature from 1150 ° C. to 1200 ° C. Therefore, it can be seen that the temperature rise of the pulverized coal particles was improved and the combustibility was improved by the increase in the blowing temperature. Also, by adjusting the particle size of pulverized coal at level 4 and keeping the pressure at the tuyere constant, the 2 kg / t-hot metal coke ratio is reduced compared to level 3 at the same blowing temperature, and pulverized by pressure measurement. It became possible to control the combustibility of charcoal.

  Further, from the results of level 2 and level 6, it was confirmed that the pressure at the tuyere increased from 360 kPa to 366 kPa by increasing the oxygen concentration during blowing from 21% to 25%. Therefore, it can be seen that the increase in the oxygen concentration improved the temperature rise of the pulverized coal particles and improved the combustibility. Furthermore, by adjusting the particle size of the pulverized coal and making the pressure at the tuyere constant, the 2 kg / t-molten coke ratio is reduced compared to level 5 of the same oxygen concentration, and the combustion of pulverized coal by pressure measurement Sex control is also possible.

  Furthermore, from the results of level 2 and level 8, it was confirmed that the pressure at the tuyere increased from 360 kPa to 367 kPa by increasing the volatile content in the pulverized coal from 15% to 25%. Therefore, it can be seen that the temperature rise of the pulverized coal particles is improved and the combustibility is also improved by the increase of the volatile matter. In addition, by adjusting the particle size of pulverized coal and keeping the pressure at the tuyere constant, the 1 kg / t-molten coke ratio is reduced compared to level 7 using the same volatile coal, and pressure measurement It became possible to control the flammability of pulverized coal.

Example 2: Example of temperature measurement
Example 2-1: Two-color Thermometer Example A tuyere 1 equipped with a temperature measuring device as a combustion state measuring device 4 was placed in a blast furnace, and continuous measurement of the particle surface temperature in the tuyere 1 was performed. Specifically, in order to confirm the combustion state of pulverized coal at the tuyere, a two-color thermometer 4 as a temperature measuring device is installed in one tuyere in an inner volume of 5000 m ³ and 38 tuyere as shown in FIG. At L = 50 mm or L = 150 mm (D = 500 mm, both in the tuyere). As measurement conditions, pulverized coal was blown from the lance at a hot metal production amount of 11500 t / day and a pulverized coal ratio of [150 kg / t-hot metal]. Further, air having a blowing temperature of 1200 ° C., a flow rate of 7000 Nm ³ / min, and an oxygen concentration of 27% was blown from the blow pipe 2. The temperature was measured continuously for 1 day.

  As is well known, the two-color thermometer 4 is a radiation thermometer that measures temperature using thermal radiation (movement of electromagnetic waves from a high-temperature object to a low-temperature object). It is one of the wavelength distribution types to obtain the temperature by measuring the temperature change of the wavelength distribution, focusing on the shift to the wavelength distribution, and in order to capture the wavelength distribution, measure the radiant energy at two wavelengths, The temperature is measured from the ratio. As the two-color thermometer 4, a two-color thermometer having a measurement range of 1000 to 3000 ° C was used.

  The measurement results are shown in FIG. In the example shown in FIG. 5, FIG. 5A is a graph showing the relationship between the particle surface temperature and time at L = 50 mm, and FIG. 5B is the graph showing the relationship between the particle surface temperature and time at L = 150 mm. It is a graph which shows a relationship. From the results shown in FIG. 5, it can be confirmed that the particle surface temperature at the tuyere during pulverized coal combustion can be continuously measured in a state in which the variation of the particle surface temperature with respect to time is small. I understood.

Moreover, the hot metal production amount of 11500 t / day, the pulverized coal ratio of [150 kg / t-hot metal], the air temperature from the blow pipe of 1200 ° C., the air flow rate of 7000 Nm ³ / min, the oxygen concentration in the air blowing is 21% Alternatively, the particle surface temperature at the tuyere when operated at 23% for 1 day each was measured at a position of L = 50 mm and 150 mm. The results are shown in FIG. 6 and FIG. In the example shown in FIG. 6, FIG. 6 (a) is a graph showing the relationship between the particle surface temperature and time at L = 50 mm and an oxygen concentration of 21%, and FIG. 6 (b) shows L = 150 mm and the oxygen concentration of 21. It is a graph which shows the relationship between the particle | grain surface temperature in% and time. In the example shown in FIG. 7, FIG. 7A is a graph showing the relationship between the particle surface temperature and time at L = 50 mm and an oxygen concentration of 23%, and FIG. 7B is L = 150 mm and the oxygen concentration of 23. It is a graph which shows the relationship between the particle | grain surface temperature in% and time. From the results shown in FIG. 6 and FIG. 7, the particle surface temperature at the tuyere is higher when the oxygen concentration shown in FIG. 6 is operated at 21% than when the oxygen concentration shown in FIG. 7 is operated at 23%. Was found to be low on average. This is considered to be because the combustibility of pulverized coal decreased.

  Next, the average of one day in two operations, when the operation is performed to maintain the flammability of the pulverized coal by measuring the particle surface temperature at the tuyere and when the operation is carried out without measuring the particle surface temperature at the tuyere The coke ratio was recorded to confirm the effect of measuring the particle surface temperature at the tuyere.

The operating conditions are 11500 t / day hot metal production, 150 kg / t-hot metal pulverized coal ratio, flow rate 7000 Nm ³ / min is constant, and any one of air temperature, oxygen concentration during air blowing, and pulverized coal volatiles is changed Then, the particle surface temperature at the position of L = 50 mm in the tuyere was measured. The weight ratio of -74 μm pulverized coal was adjusted so that the particle surface temperature at the tuyere was as constant as possible under each condition. The results are shown in Table 2 below. In Table 2, test conditions levels 4, 6, and 8 are examples in which operation is performed to maintain flammability of pulverized coal by temperature measurement at the tuyere, and test conditions levels 1, 3, 5, and 7 are It is an example at the time of operating, without implementing the temperature measurement in a mouth. In Level 2, only the average temperature was measured under the same conditions as Level 1, and no temperature adjustment was performed.

  From the results of Level 2 and Level 4, it was confirmed that the particle surface temperature at the tuyere increased from 900 ° C. to 980 ° C. by increasing the blowing temperature from 1150 ° C. to 1200 ° C. Therefore, it can be seen that the temperature rise of the pulverized coal particles was improved and the combustibility was improved by the increase in the blowing temperature. Also, by adjusting the particle size of pulverized coal at level 4 and making the particle surface temperature at the tuyere constant, the 3 kg / t-hot metal coke ratio is reduced compared to level 3 at the same blowing temperature, and the particle surface The flammability of pulverized coal can also be controlled by temperature measurement.

  In addition, from the results of Level 2 and Level 6, it was confirmed that the particle surface temperature at the tuyere increased from 900 ° C. to 1000 ° C. by increasing the oxygen concentration during blowing from 21% to 25%. Therefore, it can be seen that the increase in the oxygen concentration improved the temperature rise of the pulverized coal particles and improved the combustibility. Furthermore, by adjusting the particle size of the pulverized coal and making the particle surface temperature constant at the tuyere, the 5 kg / t-molten coke ratio is reduced compared to level 5 of the same oxygen concentration, and the particle surface temperature is measured. It became possible to control the flammability of pulverized coal.

  Moreover, it confirmed that the particle | grain surface temperature in a tuyere rose from 900 degreeC to 1010 degreeC by raising the volatile matter in pulverized coal from 15% to 25% from the result of level 2 and level 8. Therefore, it can be seen that the temperature rise of the pulverized coal particles is improved and the combustibility is also improved by the increase of the volatile matter. In addition, by adjusting the particle size of pulverized coal and keeping the particle surface temperature at the tuyere constant, the 2 kg / t-molten coke ratio is reduced compared to level 7 using coal with the same volatile content. The flammability of pulverized coal can be controlled by measuring the surface temperature.

Example 2-2: Thermocouple Thermometer Example The tuyere 1 provided with a thermocouple thermometer as the combustion state measuring device 4 was installed in a blast furnace, and the flame temperature in the tuyere 1 was continuously measured. Specifically, in order to confirm the combustion state of pulverized coal at the tuyere, in a blast furnace with an inner volume of 5000 m ³ and 38 tuyere, a thermocouple thermometer 4 is placed at one tuyere at L = 50 mm as shown in FIG. It installed in the position of L = 150mm (D = 500mm and all are in a tuyere). As measurement conditions, pulverized coal was blown from the lance at a hot metal production amount of 11500 t / day and a pulverized coal ratio of [150 kg / t-hot metal]. Further, air having a blowing temperature of 1200 ° C., a flow rate of 7000 Nm ³ / min, and an oxygen concentration of 27% was blown from the blow pipe 2. The flame temperature was measured continuously for 1 day.

  Thermocouple thermometer 4 (tungsten / rhenium thermocouple) is a metal wire made of tungsten / rhenium alloy (rhenium: 5%) and tungsten / rhenium alloy (rhenium: 26%). This is a thermometer utilizing the fact that current corresponding to the temperature difference flows when the temperature of the contact is made different, and that a thermoelectromotive force corresponding to the temperature difference is generated when one of the contacts is removed. As the thermocouple thermometer 4, a thermocouple thermometer (tungsten / rhenium thermocouple) having a measurement range of 0 to 2400 ° C. was used.

  The measurement results are shown in FIG. In the example shown in FIG. 8, FIG. 8 (a) is a graph showing the relationship between flame temperature and time at L = 50 mm, and FIG. 8 (b) shows the relationship between flame temperature and time at L = 150 mm. It is a graph to show. From the results shown in FIG. 8, it can be confirmed that the flame temperature at the tuyere during pulverized coal combustion can be continuously measured in a state where the variation of the flame temperature with respect to time is small. It was.

Moreover, the hot metal production amount of 11500 t / day, the pulverized coal ratio of [150 kg / t-hot metal], the air temperature from the blow pipe of 1200 ° C., the air flow rate of 7000 Nm ³ / min, the oxygen concentration in the air blowing is 21% Alternatively, the flame temperature at the tuyere when operated at 23% for 1 day each was measured at a position of L = 50 mm and 150 mm. The results are shown in FIG. 9 and FIG. In the example shown in FIG. 9, FIG. 9 (a) is a graph showing the relationship between flame temperature and time at L = 50 mm and oxygen concentration 21%, and FIG. 9 (b) is L = 150 mm and oxygen concentration 21%. It is a graph which shows the relationship between the flame temperature and time in. In the example shown in FIG. 10, FIG. 10 (a) is a graph showing the relationship between flame temperature and time at L = 50 mm and an oxygen concentration of 23%, and FIG. 10 (b) shows L = 150 mm and an oxygen concentration of 23%. It is a graph which shows the relationship between the flame temperature and time in. From the results of FIGS. 9 and 10, the flame temperature at the tuyere is higher when the operation is performed with the oxygen concentration shown in FIG. 9 being 21% than when the operation is performed with the oxygen concentration shown in FIG. 10 being 23%. It turned out to be low on average. This is because when the combustibility of pulverized coal decreases, unburned pulverized coal increases and the combustion temperature decreases.

  Next, the average coke ratio for one day in two operations, when the operation is performed to maintain the flammability of pulverized coal by measuring the flame temperature at the tuyere and when the operation is performed without performing the flame temperature measurement at the tuyere Was recorded to confirm the effect of flame temperature measurement at the tuyere.

The operating conditions are 11500 t / day hot metal production, 150 kg / t-hot metal pulverized coal ratio, flow rate 7000 Nm ³ / min is constant, and any one of air temperature, oxygen concentration during air blowing, and pulverized coal volatiles is changed Then, the flame temperature at the position of L = 50 mm in the tuyere was measured. The weight ratio of -74 μm pulverized coal was adjusted so that the flame temperature at the tuyere was as constant as possible under each condition. The results are shown in Table 3 below. In Table 3, the test condition levels 4, 6, and 8 are examples in the case where operation is performed to maintain the flammability of pulverized coal by measuring the flame temperature at the tuyere, and the test condition levels 1, 3, 5, and 7 are It is an example at the time of operating, without implementing flame temperature measurement in a tuyere. In Level 2, only the average flame temperature was measured under the same conditions as Level 1, and the flame temperature was not adjusted.

  From the results of Level 2 and Level 4, it was confirmed that the flame temperature at the tuyere increased from 950 ° C. to 1000 ° C. by increasing the blowing temperature from 1150 ° C. to 1200 ° C. Therefore, it can be seen that the temperature rise of the pulverized coal particles was improved and the combustibility was improved by the increase in the blowing temperature. Also, by adjusting the particle size of pulverized coal at level 4 and making the flame temperature at the tuyere constant, the 2 kg / t-hot metal coke ratio is reduced compared to level 3 at the same blowing temperature, and flame temperature measurement It became possible to control the combustibility of pulverized coal.

  Further, from the results of level 2 and level 6, it was confirmed that the flame temperature at the tuyere increased from 950 ° C. to 970 ° C. by increasing the oxygen concentration during blowing from 21% to 25%. Therefore, it can be seen that the increase in the oxygen concentration improved the temperature rise of the pulverized coal particles and improved the combustibility. Furthermore, by adjusting the particle size of the pulverized coal and making the flame temperature at the tuyere constant, the 4 kg / t-hot metal coke ratio is reduced compared to level 5 of the same oxygen concentration, and pulverized coal is measured by flame temperature measurement. It became possible to control the flammability.

  Furthermore, it was confirmed from the results of level 2 and level 8 that the flame temperature at the tuyere increased from 950 ° C. to 1010 ° C. by increasing the volatile content in the pulverized coal from 15% to 25%. Therefore, it can be seen that the temperature rise of the pulverized coal particles is improved and the combustibility is also improved by the increase of the volatile matter. In addition, by adjusting the particle size of pulverized coal and making the flame temperature constant at the tuyere, the 3 kg / t-hot metal coke ratio is reduced compared to level 7 using the same volatile coal, and the flame temperature It became possible to control the flammability of pulverized coal by measurement.

Example 3: Area ratio distribution measurement Example A tuyere 1 equipped with a camera-type area ratio measuring device as a combustion state measuring device 4 is installed in a blast furnace, and continuous measurement of the area ratio distribution of pulverized coal in the tuyere 1 is performed. did. Specifically, in order to confirm the combustion state of the pulverized coal at the tuyere, the area ratio distribution measuring device 4 is arranged at L = 50 mm as shown in FIG. 1 in one tuyere in a blast furnace with an inner volume of 5000 m ³ and 38 tuyere. Or it installed in the position of L = 150mm (D = 500mm and all are in a tuyere). As measurement conditions, pulverized coal was blown from the lance at a hot metal production amount of 11500 t / day and a pulverized coal ratio of [150 kg / t-hot metal]. Further, air having a blowing temperature of 1200 ° C., a flow rate of 7000 Nm ³ / min, and an oxygen concentration of 27% was blown from the blow pipe 2. About the measurement of a combustion condition, it implemented for 1 day continuously.
Moreover, about grasping | ascertaining of area ratio distribution, it implemented by the area ratio of the flame part area of 1000 degreeC or more in the whole pulverized coal flow. In addition, as the area ratio measuring apparatus 4, it measured by the infrared thermography of the measurement range 800-3000 degreeC, the area of 1000 degreeC or more was extracted, and the area ratio was computed.

  The measurement results are shown in FIG. In the example shown in FIG. 11, FIG. 11A is a graph showing the relationship between the area ratio at L = 50 mm and time, and FIG. 11B shows the relationship between the area ratio at L = 150 mm and time. It is a graph to show. From the results shown in FIG. 11, it can be confirmed that the area ratio at the tuyere at the time of pulverized coal combustion can be continuously measured in a state in which the variation of the area ratio with respect to time is small, so that the accuracy of the combustibility evaluation is further improved. It was.

Moreover, the hot metal production amount of 11500 t / day, the pulverized coal ratio of [150 kg / t-hot metal], the air temperature from the blow pipe of 1200 ° C., the air flow rate of 7000 Nm ³ / min, the oxygen concentration in the air blowing is 21% Alternatively, the area ratio of the flame area of 1000 ° C. or higher was measured at the positions of L = 50 mm and 150 mm in the entire pulverized coal flow at the tuyere when operated at 23% for 1 day each. The results are shown in FIGS. In the example shown in FIG. 12, FIG. 12 (a) is a graph showing the relationship between the area ratio and time at L = 50 mm and an oxygen concentration of 21%, and FIG. 12 (b) shows L = 150 mm and the oxygen concentration of 21%. It is a graph which shows the relationship between the area ratio in and time. In the example shown in FIG. 13, FIG. 13 (a) is a graph showing the relationship between the area ratio and time at L = 50 mm and an oxygen concentration of 23%, and FIG. 13 (b) shows L = 150 mm and the oxygen concentration of 23%. It is a graph which shows the relationship between the area ratio in and time. From the results of FIG. 12 and FIG. 13, the area ratio at the tuyere in the case of operation with the oxygen concentration shown in FIG. 12 being 21% is lower than that in the case of operation with the oxygen concentration shown in FIG. 13 being 23%. It turned out to be low on average. This is considered to be because the combustibility of pulverized coal decreased.

  Next, the average coke ratio for one day in two types of operation, when operating without maintaining the area ratio measurement at the tuyere and when operating to maintain the combustibility of pulverized coal by area ratio measurement at the tuyere Was recorded to confirm the effect of measuring the area ratio at the tuyere.

The operating conditions are 11500 t / day hot metal production, 150 kg / t-hot metal pulverized coal ratio, flow rate 7000 Nm ³ / min is constant, and any one of air temperature, oxygen concentration during air blowing, and pulverized coal volatiles is changed Then, the area ratio at the position of L = 50 mm in the tuyere was measured. The weight ratio of −74 μm pulverized coal was adjusted so that the area ratio at the tuyere was as constant as possible under each condition. The results are shown in Table 4 below. In Table 4, test conditions levels 4, 6, and 8 are examples in which operation is performed to maintain flammability of pulverized coal by area ratio measurement at the tuyere, and test condition levels 1, 3, 5, and 7 are It is an example at the time of operating, without implementing the area ratio measurement in a tuyere. In Level 2, only the average area ratio was measured under the same conditions as Level 1, and the area ratio was not adjusted.

  From the results of Level 2 and Level 4, it was confirmed that the area ratio at the tuyere increased from 0.08 to 0.12 by increasing the blowing temperature from 1150 ° C to 1200 ° C. Therefore, it can be seen that the temperature rise of the pulverized coal particles was improved and the combustibility was improved by the increase in the blowing temperature. Moreover, by adjusting the particle size of pulverized coal at level 4 and making the area ratio at the tuyere constant, the 2 kg / t-hot metal coke ratio is reduced compared to level 3 at the same blowing temperature, and the area ratio measurement It became possible to control the combustibility of pulverized coal.

  Further, from the results of level 2 and level 6, it was confirmed that the area ratio at the tuyere increased from 0.08 to 0.14 by increasing the oxygen concentration during blowing from 21% to 25%. Therefore, it can be seen that the increase in the oxygen concentration improved the temperature rise of the pulverized coal particles and improved the combustibility. Furthermore, by adjusting the particle size of the pulverized coal and keeping the area ratio at the tuyere constant, the 3 kg / t-hot metal coke ratio is reduced as compared with level 5 of the same oxygen concentration, and pulverized coal by area ratio measurement. It became possible to control the flammability.

  Further, from the results of Level 2 and Level 8, it was confirmed that the area ratio at the tuyere increased from 0.08 to 0.15 by increasing the volatile content in the pulverized coal from 15% to 25%. Therefore, it can be seen that the temperature rise of the pulverized coal particles is improved and the combustibility is also improved by the increase of the volatile matter. In addition, by adjusting the particle size of pulverized coal and keeping the area ratio at the tuyere constant, the 3 kg / t-hot metal coke ratio is reduced compared to level 7 using the same volatile coal, and the area ratio It became possible to control the flammability of pulverized coal by measurement.

Example 4: Image Analysis Example A tuyere 1 equipped with an image analysis device as a combustion state measuring device 4 was placed in a blast furnace, and continuous measurement of the area of the flaky coal in the tuyere 1 was performed. Specifically, in order to confirm the combustion state of the pulverized coal at the tuyere, the image analysis apparatus 4 is arranged at L = 50 mm or L as shown in FIG. 1 in one tuyere in a blast furnace with an inner volume of 5000 m ³ and 38 tuyere. = 150 mm (D = 500 mm, both in the tuyere). As measurement conditions, pulverized coal was blown from the lance at a hot metal production amount of 11500 t / day and a pulverized coal ratio of [150 kg / t-hot metal]. Further, air having a blowing temperature of 1200 ° C., a flow rate of 7000 Nm ³ / min, and an oxygen concentration of 27% was blown from the blow pipe 2. About the measurement of a combustion condition, it implemented for 1 day continuously.

  As for grasping the combustion state, in the image, the area of the unburned pulverized coal is A, the area of the flame part generated by the combustion of the pulverized coal is B, and the area of the entire pulverized coal main body of the flame part area B (A + B) Was carried out at an area ratio (B / (A + B)). The area ratio measurement by the image analysis device 4 was performed by photographing the pulverized coal mainstream and the flame part with a high-speed camera and calculating the area ratio with image analysis software.

  The measurement results are shown in FIG. In the example shown in FIG. 14, FIG. 14A is a graph showing the relationship between the area ratio at L = 50 mm and time, and FIG. 14B is the graph showing the relationship between the area ratio at L = 150 mm and time. It is a graph to show. From the results shown in FIG. 14, it can be confirmed that the area ratio at the tuyere at the time of pulverized coal combustion can be continuously measured in a state where the variation of the area ratio with respect to time is small. It was.

Moreover, the hot metal production amount of 11500 t / day, the pulverized coal ratio of [150 kg / t-hot metal], the air temperature from the blow pipe of 1200 ° C., the air flow rate of 7000 Nm ³ / min, the oxygen concentration in the air blowing is 21% Alternatively, the area ratio of the flame area in the area of the entire mainstream of pulverized coal at the tuyere when operated at 23% for 1 day each was measured at a position of L = 50 mm and 150 mm. The results are shown in FIG. 15 and FIG. In the example shown in FIG. 15, FIG. 15A is a graph showing the relationship between the area ratio and time at L = 50 mm and an oxygen concentration of 21%, and FIG. 15B is a graph showing L = 150 mm and the oxygen concentration of 21%. It is a graph which shows the relationship between the area ratio in and time. In the example shown in FIG. 16, FIG. 16 (a) is a graph showing the relationship between the area ratio and time at L = 50 mm and an oxygen concentration of 23%, and FIG. 16 (b) is L = 150 mm and the oxygen concentration of 23%. It is a graph which shows the relationship between the area ratio in and time. From the results of FIGS. 15 and 16, the area ratio at the tuyere is greater when the operation is performed with the oxygen concentration shown in FIG. 15 being 21% than when the operation is performed with the oxygen concentration being 23% shown in FIG. 16. It turned out to be low on average. This is considered to be because the combustibility of pulverized coal decreased.

  Next, the average coke ratio for one day in two types of operation, when operating without maintaining the area ratio measurement at the tuyere and when operating to maintain the combustibility of pulverized coal by area ratio measurement at the tuyere Was recorded to confirm the effect of measuring the area ratio at the tuyere.

The operating conditions are 11500 t / day hot metal production, 150 kg / t-hot metal pulverized coal ratio, flow rate 7000 Nm ³ / min is constant, and any one of air temperature, oxygen concentration during air blowing, and pulverized coal volatiles is changed Then, the area ratio at the position of L = 50 mm in the tuyere was measured. The weight ratio of −74 μm pulverized coal was adjusted so that the area ratio at the tuyere was as constant as possible under each condition. The results are shown in Table 5 below. In Table 5, test conditions levels 4, 6, and 8 are examples when the operation is performed to maintain flammability of pulverized coal by area ratio measurement at the tuyere, and test condition levels 1, 3, 5, and 7 are It is an example at the time of operating, without implementing the area ratio measurement in a tuyere. In Level 2, only the average area ratio was measured under the same conditions as Level 1, and the area ratio was not adjusted.

  From the results of Level 2 and Level 4, it was confirmed that the area ratio at the tuyere increased from 0.25 to 0.31 by increasing the blowing temperature from 1150 ° C to 1200 ° C. Therefore, it can be seen that the temperature rise of the pulverized coal particles was improved and the combustibility was improved by the increase in the blowing temperature. Moreover, by adjusting the particle size of pulverized coal at level 4 and making the area ratio at the tuyere constant, the 2 kg / t-hot metal coke ratio is reduced compared to level 3 at the same blowing temperature, and the area ratio measurement It became possible to control the combustibility of pulverized coal.

  Further, from the results of Level 2 and Level 6, it was confirmed that the area ratio at the tuyere increased from 0.25 to 0.32 by increasing the oxygen concentration in the blowing from 21% to 25%. Therefore, it can be seen that the increase in the oxygen concentration improved the temperature rise of the pulverized coal particles and improved the combustibility. Furthermore, by adjusting the particle size of the pulverized coal and keeping the area ratio at the tuyere constant, the 3 kg / t-hot metal coke ratio is reduced as compared with level 5 of the same oxygen concentration, and pulverized coal by area ratio measurement. It became possible to control the flammability.

  Furthermore, from the results of Level 2 and Level 8, it was confirmed that the area ratio at the tuyere increased from 0.25 to 0.31 by increasing the volatile content in the pulverized coal from 15% to 25%. Therefore, it can be seen that the temperature rise of the pulverized coal particles is improved and the combustibility is also improved by the increase of the volatile matter. In addition, by adjusting the particle size of pulverized coal and keeping the area ratio at the tuyere constant, the 3 kg / t-hot metal coke ratio is reduced compared to level 7 using the same volatile coal, and the area ratio It became possible to control the flammability of pulverized coal by measurement.

  According to the combustion status measurement method of the present invention, the combustion status of solid fuel such as pulverized coal can be accurately confirmed at the tuyere. Therefore, it becomes possible to accurately control the combustibility of solid fuel such as pulverized coal based on the confirmed combustion condition, and the combustion condition measuring method of the present invention is suitable for various fields such as a blast furnace that requires combustibility control. Can be used.

1 tuyere 2 blow pipe 3 lance 4 combustion state measuring device (pressure measuring device, temperature measuring device, area ratio distribution measuring device, image analysis device)

The present invention relates to a combustion state measuring method and a combustion state measuring system for measuring a combustion state of a solid fuel such as pulverized coal or a flammable gas such as LNG (Liquefied Natural Gas) at a blast furnace tuyere.

The present invention has been made paying attention to the above-described problems, and provides a combustion state measuring method and a combustion state measuring system that enable confirmation of the combustion state at the tuyere during pulverized coal combustion. It is the purpose.

That is, according to the present invention, when the distance D from the tip of the lance to the tip of the tuyere is between 0 and 500 mm, the combustion condition measuring device is installed at a position of a distance L (0 mm <L <D) from the tip of the lance. It is a combustion state measuring method characterized by continuously measuring the pulverized coal combustion state at the tuyere with a measuring device.
The present invention also provides a tuyere installed on the wall of the blast furnace, a blow pipe attached to the tuyere, a lance attached to the wall of the blow pipe, and a tip between the tip of the lance and the tip of the tuyere. A combustion state measuring system comprising a combustion state measuring device mounted on a blow pipe or tuyere wall.

In the combustion state measuring method according to the present invention,
(1) The combustion state measuring device is a pressure gauge, and the pulverized coal combustion state is a pressure measured using a pressure gauge,
(2) The combustion state measuring device is a temperature measuring device, and the pulverized coal combustion state is a temperature measured using a temperature measuring device,
(3) The temperature measuring device is a two-color thermometer that measures particle surface temperature from luminance or a thermocouple that measures flame temperature,
(4) The combustion state measuring device is an area ratio distribution measuring device, and the pulverized coal combustion state is an area ratio of pulverized coal measured using an area ratio distribution measuring device,
(5) The combustion state measuring device is an image analysis device, and the pulverized coal combustion state is a flame part area of pulverized coal measured using an image analysis device,
However, it can be considered as a more preferable solution.
In the combustion status measurement system according to the present invention,
(6) When the distance D from the tip of the lance to the tip of the tuyere is between 0 and 500 mm, a combustion state measuring device is installed at a position of distance L (0 mm <L <D) from the tip of the lance. Continuously measuring the pulverized coal combustion state at the tuyere,
However, it can be considered as a more preferable solution.

According to the combustion state measurement method and the combustion state measurement system of the present invention, the combustion state of solid fuel such as pulverized coal can be accurately confirmed at the tuyere. Therefore, it is possible to accurately control the combustibility of solid fuel such as pulverized coal based on the confirmed combustion state, and in various fields such as a blast furnace that requires control of combustibility, the combustion state measuring method and combustion of the present invention A situation measurement system can be suitably used.

Claims (6)

  When the distance D from the tip of the lance to the tip of the tuyere is between 0 and 500 mm, a combustion condition measuring device is installed at a distance L (0 mm <L <D) from the tip of the lance. A combustion state measuring method characterized by continuously measuring a pulverized coal combustion state.   The combustion state measuring method according to claim 1, wherein the combustion state measuring device is a pressure gauge, and the pulverized coal combustion state is a pressure measured using a pressure gauge.   The combustion state measuring method according to claim 1, wherein the combustion state measuring device is a temperature measuring device, and the pulverized coal combustion state is a temperature measured using a temperature measuring device.   4. The combustion state measuring method according to claim 3, wherein the temperature measuring device is a two-color thermometer for measuring particle surface temperature from luminance or a thermocouple for measuring flame temperature.   The combustion state according to claim 1, wherein the combustion state measuring device is an area ratio distribution measuring device, and the pulverized coal combustion state is an area ratio of pulverized coal measured using an area ratio distribution measuring device. Measuring method.   The combustion state measuring method according to claim 1, wherein the combustion state measuring device is an image analysis device, and the pulverized coal combustion state is a flame area of pulverized coal measured using the image analysis device.

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